Tolerances to BS EN 10296-2 for welded stainless steel tube

Introduction

Unlike the standards for flat and long products, the standards for stainless steel tube products contain information on tolerances. This is possibly because the tolerance requirements for tubes are simpler to define.

Straightness

OD Deviation from straightness on tube length L
> 33.7 mm 0.0020 L
< 33.7 mm Agreed at time of  enquiry and order

Example 50mm dia tube x 6000 mm long maximum deviation from straightness = 12 mm

A tighter tolerance of 0.0015 L can be agreed at time of order and enquiry.

Outside Diameter 

OD Tolerance on OD including ovality
< 168.3 mm ± 0.75 % or ± 0.3 mm whichever is the greater
> 168.3 mm ± 1.0 %

A tighter tolerance can be agreed at the time of enquiry and order on tubes of < 114.3 mm of ± 0.5 % or ± 0.15 mm whichever is the greater.

Wall Thickness

For all tube sizes tolerance on wall thickness is ± 10 % or ± 0.2 mm whichever is the greater.

Weld Seam Height

The outside weld bead of HF welded tube shall be removed completely i.e. flush with the outside surface of the tube.

The maximum heights of the external and internal weld seams shall otherwise be as given in the table below:

Weld finish Maximum height of weld seam
Wall thickness (T) < 8 mm Wall thickness (T) > 8 mm
Finish A 0.20 T + 0.5 T/3
Finish B for D < 114.3 mm 0.06 T + 0.3 -
Finish B for D > 114.3 mm 0.05 T + 0.5 T/6
Finish C 0.15 -

Finish A - Internal and external weld bead not removed

Finish B - External weld bead removed internal weld bead not removed

Finish C - Internal and external weld bead rolled or removed

Finish A shall not be used on HF welded tube

Length

Type of length Length L Tolerance
Standard 6000 mm +100/-0
Random Length range by arrangement
Exact < 6000 mm +5/-0
6000 < L < 12000 +10/-0
>12000 by agreement

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